If you’re wondering, the original filename is “NSRevisionsBackground.png” and it’s from the Versions package, unlike the Mac OS X 10.7 default Fuji Mountain wallpaper that we posted yesterday which is found in /Library/Desktop Pictures/ in the Developer Preview.

The galaxy wallpaper is the background image in Versions, the new document versioning utility included in Lion that behaves much like a Time Machine for individual documents. You can see it in this screenshot from Apple’s Lion preview:

As usual, Apple finds gorgeous wallpapers for your Mac OS X desktop background. Apparently there aren’t many different pictures included in Lion yet (even the lotus flower from the “Back to the Mac” preview is said to not be included) but we’ll let you know as more become available.